The present invention relates to a bicycle pedal assembly of a type which makes bicycling more effective by providing improved possibilities for pulling during the upward phase of a pedal revolution. At the same time provisions can be made so that the foot of the bicyclist is not clamped in such a manner that it is difficult to be released when it is required in a special situation.
There are known numerous previous pedal devices constructed in order to ease and increase the efficiency of the work/movements which a bicyclist has to do. It is self-evident that many such devices often will operate poorly or reverse to the desired effect, since the basic physical work to be executed, cannot be reduced, neither in theory nor in practice. Therefore, a number of such inventions will rather have a negative effect by adding to the bicycle an extra mass (weight) to be carried along, as well as additional friction without any particularly favorable effect to be detected.
However, measures of a sensible character will usually have one of two possible goals, i.e. either
(a) providing a different "gear ratio", or PA1 (b) providing improved ergonomics.
The two items (a) and (b) may of course also merge into each other, in the sense that the idea of changing a gear ratio, for example by extending a moment arm (which lowers the force requirements, i.e. the requirements for muscular strength, but imposes a longer travel or path for the movement), often will be caused by ergonomic considerations.
However, finding a favorable manner of moving, e.g. so that larger or more muscle groups can be put into action, or so that a "narrow" movement can be changed to a more "free", "open" or unstrained movement, clearly has its own value, independent of moment arm extensions or gear ratios.
As is well known, a quite ordinary bicycle pedal only provides the possibility for downwardly directed force influence from a foot, i.e. in the downward phase, and the two pedals will then operate in an alternating mode, with a resting phase in the upward motion. The classical "racing" pedal is also well known, with a so-called "spurt cleat" and a toe clip with a strap, for strong fixing of the foot to the pedal. Thereby, a possibility also is provided for a pulling action by the foot in the upward phase, but it is not quite certain that the upward pulling possibility provided by the classical racing device gives the best possible ergonomics for the legs/feet in the upward pulling phase. Also, in special situations it is clearly unfortunate that the feet are fixed solidly to the bicycle. Quite a few bicyclists have tipped over because they have not been able to release the toe straps and pull their feet out quickly enough.
More modern variants of such racing pedals have been constructed, which operate without toe clip and strap, but these variants provide substantially the same movement mode, and anyhow, these variants also require a certain technique for release. An example of such a more recent pedal variant is indicated in EP application No. 169,080, which shows a spurt cleat arrangement with a catch feature which can be used both with and without a traditional toe clip.
More particularly it must be mentioned, for an illumination of the art prior to the present invention, that some devices have been conceived to connect the heel part of the foot more directly to the pedal. For example, GB 485,748 shows a device intended to operate partly as a heel rest, partly to provide a possibility for pulling upwardly. However, this device is only an extra equipment to be mounted on an ordinary pedal, and it provides rather limited possibilities for pulling upwardly due to a rather loose hold of the foot with only a bow up behind the heel. The pedal axle means is quite traditional.
Also DE Offenlegungsschrift no. 3,445,043 shows a "heel catch" arranged to provide a possibility for pulling upwardly, and the principle in this case is rather similar to the one mentioned above, with a bow or catch laid around the heel some distance up on the foot. The how is shown schematically attached to an ordinary pedal, presumably with a fixed connection. In reality this device will operate in approximately the same manner as the already mentioned classical "racing" principle, where a corresponding transfer of force from the heel to an ordinary pedal takes place via a tight-fitting shoe with a very stiff sole, which sole is strapped tight to the pedal by means of spurt cleat and strap. However, in DE 3,445,043 no such fixing or strapping appears, and it seems that the ergonomics in this case actually is poorer than in the classical racing case, since the forward part of the foot is loose, providing a more unfavorable use of muscles in the upward pulling phase than the fixed connection of the racing pedal. DE 3,445,043 will be regarded as the prior art most closely connected with the present invention, due to the heel upstroke provision shown.
Another type of holding a shoe heel is shown in DE 62,131, where a shoe heel with a hole and a recess is used, into which a tip and a spring at the end of a rearwardly protruding rail from the pedal may enter. However, this equipment which also is an extra equipment, is primarily intended to hold the foot in place on the pedal, and can hardly be intended to provide the option of pulling upwards at all, since the connection to the heel is mechanically weak. The pedal axle means is of the ordinary type.
One special pedal of a relatively long and integral design is known from DE patent no. 3,149,345. The length of the pedal is approximately half the length of a foot, and the pedal axle means is placed approximately in the middle. The point of this new "racing" pedal, which is intended for use together with bicycling shoes with a specially constructed, rigid mounting pate with engagement details, mounted on the shoe underside, is to provide a "safety pedal" for quick release by twisting sideways. The pedal axle means is of the traditional type, and it also seems somewhat unfortunate when considering the downward pushing phase, that the toeball part of the foot is located far in front of the axle means. The shoe will hardly be particularly suited for walking. The upward pulling phase can be used, however, with a mode of movement which supposedly is not very favorable, probably also in this case less favorable than the classical "racing" pedal.
From FR 989,397, FR 796,362 and CH 540,812 are known pedal systems for providing moment arm extension means for the pedal arm in the downstroke, by means of freewheel devices in the pedal axle. In these cases the foot toeball part must be placed forward of the pedal axle to achieve the intended effect. Ergonomics will not be substantially altered in such cases, mostly only a forward shift of the foot movement circle (which results in a necessary change of sitting position), together with a long forward pedal arm (which gives the same effect as a lower gear ratio).